At first they are hatchlings but how exactly do they grow? They are robotic organisms but their metal isn't exactly earth metal but alien cybertonian metal. I don't think it's the same thing. Do they have some kind of metal skin that grows like an human organism or do they keep upgrading with parts? I ask this because I first thought of this when in DOTM Megatron fed whatever it was to the little hatchlings like they were little growing organisms.